Pneumatic tires typically include a tire casing with sidewalls that extend radially inward from a crown portion and terminate at bead areas. In an installed condition of the pneumatic tire, the bead areas are positioned on or along corresponding bead seats of an associated wheel. The bead areas are dimensioned to tightly interengage the bead seats. In this manner, a substantially air-tight assembly can be formed between the pneumatic tire and the associated wheel. As such, a pneumatic tire and wheel assembly can be formed that is capable of retaining a quantity of air at an elevated pressure level for an extended period of time.
Additionally, the interengagement between the bead areas of a pneumatic tire and the corresponding bead seats of an associated wheel should be sufficiently robust to transmit the full torque acting on the pneumatic tire without permitting relative movement between the pneumatic tire and the associated wheel. In general, the torque acting on the pneumatic tire is developed during use of the vehicle due to the transmission of forces between the associated wheel and the road surface. It will be appreciated that such torque can be generated during both acceleration and deceleration of the vehicle.
In many cases, wheels are manufactured to industry standard dimensions and include bead seats having established configurations and/or constructions. To ensure that a robust interconnection can be formed between a pneumatic tire and an associated wheel, the bead areas of pneumatic tires are dimensioned such that a portion of the rubber forming the bead areas is radially compressed along the bead seats when installed. Substantially-inextensible reinforcing elements are typically embedded within the bead areas such that the portions of rubber that are compressed along the bead seats are disposed radially inwardly of the reinforcing elements. Such inextensible reinforcing elements typically take the form of endless, annular tensile members that are commonly referred to in the art as bead cores.
In an installed condition of the pneumatic tire, the bead cores are placed in tension due, at least in part, to the compression of the portions of rubber that are disposed radially inward of the bead cores and engage the bead seats of the corresponding wheel. To establish and maintain a robust interengagement between the pneumatic tire and the associated wheel, the bead cores are constructed to be substantially inextensible under the tensile loads incurred during installation and use.
Typically, bead cores are made of one or more steel wires arranged in an annular configuration, such as in the shape of a circular hoop, for example, and can have any one of a variety of known cross-sectional shapes, such as circular, square, rectangular, trapezoidal, hexagonal or variations thereof. In some cases, bead cores are formed from a relatively short length of wire or rod having opposing ends that are welded or otherwise joined together to form a solid ring. In other cases, bead cores are formed from one or more elongated lengths of smaller diameter wire that are wrapped and wound into an annular ring.
Although known pneumatic tire constructions generally operate satisfactorily, it remains desirable to increase pneumatic tire performance, and to reduce weight and/or manufacturing costs of pneumatic tires over known constructions. As such, the subject matter of the present disclosure seeks to provide these and/or other benefits and/or improvements over known pneumatic tire constructions.